The present invention relates to a new, portable spreader-type rescue tool for applying high push/pull forces in moving, bending or opening up a wrecked vehicle to free a person trapped in it.
This general type of tool is shown and described in U.S. Pat. No. 3,819,153 issued June 25, 1974 on "Rescue Tool" to which reference may be had for a more detailed description of specific uses of it.
This is one of a number of specialized tools carried by paramedics, firemen and others for freeing accident victims. It must be portable, light enough for one person to carry, and capable of exerting extremely high push/pull forces, enough for example to rip a door completely off a vehicle along the hinged edge, or to pull a steering column forward through the windshield opening.
These spreading tools have a pair of pivoted arms with powerful hydraulic drive mechanism for forcing them together or apart. They have narrow tips which can be forced into small openings such as between a door and frame and must be capable of exerting pushing and pulling forces of 20,000 pounds or more.
Attempts have been made to lighten the weight of these tools by using aluminum alloy arms, with hardened steel jaw tips. Prior to the present invention, attempts to obtain push/pull forces of this magnitude in a tool light enough to be readily portable have resulted in breakage of the aluminum arms or loosening of the tips after a few operations.
Where the tool is used in a pull mode, as for tensioning chain sections attached between a front bumper and a steering wheel pinned agaist an accident victim, clevises are used to connect chain sections between the respective tool arms and the bumper and steering column. Conventional clevises have had a number of drawbacks, including loose clevis pins which may become lost in the confusion of an accident scene.
Previous attempts to reduce the weight of these rescue tools by mounting the spreading tips in aluminum alloy arms have not been completely satisfactory.